High explosive anti-tank (HEAT) weapons have been in the American arsenal since World War II. The penetration mechanism within the HEAT warhead is the shaped-charge. A shaped-charge consists of a thin-walled metallic liner with high explosive molded around the outside of it. When the warhead strikes the target, the explosive is detonated. A shock front passes over the liner causing the liner to collapse upon itself. Under the extreme pressures of the explosion, the metallic liner behaves much like a fluid. When opposing sides of the coverging liner meet during collapse, a portion of the metal liner is "squirted" forward with high velocity (approx. 9 km/sec). This material is called the jet, and constitutes the penetrating element of the warhead.
The shaped charge is typically an axisymmetric warhead. That is to say, the phenomenon of asymmetric liner collapse is usually considered detrimental to warhead performance. This is however, not always the case. Applicant recently studied asymmetric liner collapse in hopes of producing a shaped-charge warhead with controllable jet deflection charcteristics using techniques of asymmetric warhead construction. In these experiments, the tests were carried out by first designing a warhead with asymmetric characteristics, building such a warhead, testing the warhead, and gathering data from the tests.
Warhead development can become a very slow process using traditional techniques. Two major drawbacks which were realized while fabricating asymmetric warhead bodies were fabrication time and cost. Both drawbacks result because of the fact that the asymmetric confinement bodies cannot be made on a lathe because of their asymmetric nature. Rather, a more time consuming process was required on a milling machine where the cost per confinement body was approximately $2000 (compared with $300 for a symmetric confinement). Once a final design exists, a machine can be modified to produce the asymmetric confinements cheaply en masse. However, experimental prototypes require individual attention and as such, are subject to present machinery limitations. During the developmental stages of the project where routine upgrading of the design occurs, refabrication of each new upgraded design becomes an expensive and time consuming proposition.